What is the basic operating weight of an aircraft?

The basic operating weight of an aircraft refers to the weight of the aircraft itself minus the payload and fuel. This measurement includes the airframe, engines, and necessary operating equipment, as well as any required crew members, but it does not consider passengers, cargo, or fuel.

Understanding basic operating weight is crucial as it provides a baseline for calculating various performance metrics, such as range and load capacities, and ensuring that the aircraft operates within safe limits during flights.

In contrast, the other options don't accurately define basic operating weight. The maximum fuel only represents a different aspect of the aircraft's weight, and the maximum takeoff weight pertains to the total weight during takeoff, which includes fuel, passengers, and cargo. The weight of the aircraft when it is empty, technically referred to as "empty weight," does not include operational equipment or crew, and thus is not equivalent to the basic operating weight.